Cable operated hydraulic actuator



March 24, 1964 R. w. SCHUFF CABLE OPERATED HYDRAULIC ACTUATOR 5 Sheets-Sheet 1 Filed Jan. 17, 1965 INVENTOR. RICHARD w. SCHUFF March 24, 1964 R. w. SCHUFF CABLE OPERATED HYDRAULIC ACTUATOR Filed Jan. 17, 1963 5 Sheets-Sheet 2 INVENTOR. RICHARD W. SCHUFF R. W. SCHUFF CABLE OPERATED HYDRAULIC ACTUATOR March 24, 1964 5 Sheets-She Filed Jan. 1'7, 1963 INVENTOR. RICHARD. W. SC HUFF March 24, 1964 R. w. SCHUFF CABLE OPERATED HYDRAULIC ACTUATOR Filed Jan. 17, 1963 5 Sheets-Sheet 4 INVENTOR. RICHARD W. SCHUFF United States Patent 3,126,115 CABLE OFERATED HYDRAULIC ACTUATUR Richard W. Schuii, 5026 E. Cherry Lynn Road, Ihoenix, Ariz. Filed Jan. 17, 1963, Ser. No. 252,144 12 Claims. (Cl. 214-656) This invention relates to a cable operated hydraulic actuator and more particularly to a cable operated hydraulic actuator which is especially adapted for use in actuating clams at the lower end of an excavating mechanism suspended by a cable and used to dig deep wells or other holes in the ground.

Heretofore, prior art devices have comprised the usual cable tools comprising hydraulic cylinders carried by said tools to actuate digging clams on the lower ends thereof. Such hydraulic cylinders have been provided with pressure fluid conductors which are carried by the cable which suspends the tool thereby necessitating the handling of the cable over a crown sheave structure or handling the cable in connection with a reel above ground and providing a pressure accumulator and valve mechanism which is operated above ground, remotely, to actuate the clams when closing at the bottom of a hole being excavated by the tool.

The remote actuation of a hydraulic cylinder down a deep hole, in order to close clams at the lower end of a tool, requires the transfer of pressure fluid to the hydraulic cylinder and exhaust of fluid therefrom. With lengthy conduits the attendant pressure loses and maintenance of such equipment is a considerable problem. This becomes more acute as the tool is used to excavate in deep holes. Furthermore, such equipment, utilizing remotely actuated hydraulic cylinders in an excavating tool, require additional equipment, namely, means for creating pressure in connection with a supply of hydraulic fluid and this equipment is maintained above ground during which time, the conduits communicating therewith and with the hydraulic cylinder below the ground, are continually flexed when conducting hydraulic fluid at high pressures.

Accordingly, it is an object of the present invention to provide a cable operated hydraulic actuator wherein the cable which normally raises the tool up and down in a hole being excavated is actuated by a powerful winch which is disposed on a truck or other piece of equipment above ground; said winch providing suflicient force on the cable to actuate a hydraulic charge cylinder in the tool which charge cylinder stores energy in an accumulator in the tool and the accumulator communicates through a hydraulic valve to supply pressure fluid to a second hydraulic cylinder which actuates clams on the lower end of the tool when the clams support the tool in the bottom of the hole and create a slack condition on the charge cylinder and thereby lower the stress relative thereto.

Another object of the invention is to provide a cable operated hydraulic actuator wherein the winch cable powers a hydraulic system internally of the tool which efiiciently opens and closes the clams on the lower end of the tool so that remote hydraulic actuation of the clam closing hydraulic cylinder is eliminated thereby alleviating the problems attendant to the lengthy flexible hydraulic pressure fluid conduits extending from the tool to a disposition above the ground when the tool is operating in deep holes.

Another object of the invention is to provide a cable operated hydraulic actuator which is particularly adapted for use in actuating clams on the bottom of a well drilling tool and wherein the power to close the clams is automatically stored in the tool by force of the cable which forces the tool against a stop when the tool is drawn upwardly out of the hole thereby providing an abutment 2 to retract the plunger of a pressure fluid charging cylinder and whereby means is provided when the clams rest in the bottom of the hole to actuate a pressure fluid conducting system to energize a clam actuating cylinder for closing the clams.

Another object of the invention is to provide a cable operated hydraulic actuator which is particularly adapted for use in automatically operating digging clams on the lower end of a deep well drilling tool.

Another object of the invention is to provide a cable operated hydraulic actuator wherein a novel crown sheave stop block is provided with means angularly disposed-to the horizontal and forming an abutment for the upward end of a cable tool whereby the cable tool, when engaging said abutment is forced laterally at an acute angle to the vertical and whereupon, in this position, the clams at the lower end of the tool are automatically caused to open so that the tool, as it emerges from the hole swings laterally and automatically releases its load laterally of the hole being drilled.

Another object of the invention is to provide a novel pressure fluid system adapted for intermittent charging by force applied through a cable which suspends a drill tool casing in which said system is disposed.

Another object of the invention is to provide a very simple and economical cable operated hydraulic actuator for actuating digging clams on the lower end of a well drilling cable tool.

Another object of the invention is to provide a cable operated hydraulic actuator for actuating clams on the lower end of a well drilling cable tool which saves considerable time and consequently, money in the drilling of deep wells by said cable tool.

Another object of the invention is to provide a cable operated hydraulic actuator wherein force applied to a cable which suspends a conventional well drilling cable tool, automatically causes operation of digging clams on the lower end of the tool and automatically causes the tool to swing away from the hole and unload the clams whereby the manual attention to the closing of the clams at the bottom of the hole and opening of the clams to dump the load at the top of the hole is completely eliminated.

Other objects and advantages of the invent-ion may be apparent from the following specification, appended claims, and accompanying drawings, in which:

FIG. 1 is a side elevational view of a cable operated hydraulic actuator of the present invention mounted on a truck and incorporated in a conventional well drilling cable tool having digging clams on the lower end thereof;

FIG. 2 is a view taken from the line 2-2 of FIG. 1 showing the cable tool swung into an acute angular position relative to the vertical and laterally of a hole being dug whereby the lower end of the tool carries the clams and the clams are dumped at one side of the hole;

FIG. 3 is a fragmentary view of the upper end of the cable tool, shown in FIG. 2, but showing a modification thereof;

FIG. 4 is an enlarged horizontal sectional view taken from the line 4-4 of FIG. 1 showing features of the hydraulic equipment internally of the tool casing;

'FIG. 5 is an enlarged fragmentary side elevational view of the lower end of the cable tool and the digging clams carried thereby;

FIG. 6 is a vertical sectional view of the cable tool casing of the invention showing the clam actuating hydraulic equipment internally thereof;

FIG. 6a is a diagrammatic view showing the hydraulic equipment of the invention in a position wherein the tool may be above ground with the clams in open position and wherein the charge cylinder of the system has forced the clams actuating cylinder to open the clams and to ice force a hydraulic pressure charge into the accumulator in communication therewith.

FIG. 7 is a diagrammatic view of a modified form of the hydraulic clam actuating equipment of the invention shown in one position wherein the tool may be at the bottom of a hole and wherein the clams are actuated to closed position ready for the tool to be elevated to the surface;

FIG. 8 is a diagrammatic view, similar to FIG. 7, but showing the hydraulic equipment in a position wherein the tool may be above ground with the clams in open position and wherein the charge cylinder has forced the clam actuating cylinder to open the clam and to force a hydraulic pressure charge into the accumulator;

FIG. 9 is a fragmentary vertical sectional view of a modified form of the invention showing the cable tool casing containing part of the hydraulic actuating equipment and showing clams in connection with the lower portion of the casing and in open position;

FIG. 10 is a fragmentary vertical sectional view of an upper portion of the cable tool casing of the invention and showing the remaining hydraulic equipment therein which is omitted fragmentarily from the showing in FIG.

FIG. ll is a diagrammatic view of the hydraulic equipment of the modified structure shown in FIGS. 9 and 10 and showing the hydraulic equipment in position to cause closing of the clams;

FIG. 12 is a diagrammatic view similar to FIG. 11 and showing the hydraulic equipment of the invention in a position wherein the charge cylinder is ready to cause opening of the clams and the forcing of a hydraulic pressure charge into the accumulator; and

FIG. 13 is a view similar to FIG. 12 and showing the hydraulic system of the invention in a position in which the clams are partially closed and in which the plunger of the charge cylinder has made a partial stroke during either phase of the operating cycle, as shown in FEGS. 11 and 12.

The cable operated hydraulic actuator of the present invention generally comprises a cable tool drill casing 10 having digging clams 12 pivotally mounted and hydraulically actuated at a lower end 14 of the casing 10. The clams 12 are hydraulically actuated by means internally of the casing 10, as will be hereinafter described, and the casing 10 is suspended by a fitting 16 coupled to a cable 18 which passes over a crown sheave 2t) and is connected to a power operated winch 22. As will be hereinafter described, the fitting 16 is coupled to a plunger of the hydraulic system internally of the casing 10 whereby force applied by the Winch 22. causes sufiicient tension in the cable 18 to actuate a plunger of a charge cylinder in the casing 10 to store pressure in an accumulator which ressure is later utilized to close the clams 12 when they are in the bottom of a hole A, shown in FIG. 2 of the drawings.

Power is applied to the cable 18 to actuate the hydraulic system in the casing 10 when an upper end 24 of the casing 10 is forced against a surface 26 of a crown sheave stop block 28, it being noted that the surface 26 is at an acute angle to the horizontal and disposed below the crown sheave over which the cable 18 is forcefully drawn by the winch 22. Thus, when the upper end of the casing 10 abuts the stop block 28 and tension is applied to the cable 18, the casing swings into the position B shown in FIG. 2 of the drawings, at an acute angle to the vertical and laterally of the hole A so that the clams 12 may be opened and dump their load in a pile C laterally of the hole A, all this operation being automatic.

The crown sheave 20 is pivotally mounted on the vertical mast 30 and the stop block 28 is a hollow tubular member extending downwardly from a bearing support 32 carried on the upper end of the mast 30. The cable 13 extends downwardly through the hollow stop block 28,

all as shown best in FIGS. 1 and 2 of the drawings. The mast 30 is pivotally connected by means of the pin 34 with a plunger 36 of a long hydraulic cylinder 38 which is pivotally mounted by means of a pin 42 to a frame 44 of a truck 46. The lower end of the mast 30 is pivotally mounted by a pin 48 to an upwardly extending portion 54) of the chassis of the truck 44. Thus, retraction of the plunger 36 by the cylinder 38 will tilt the mast 30 forwardly and permit it to rest on an upwardly extending support 52 slightly above the cab of the truck 46. In this position, the entire drill rig, including the cable operated hydraulic actuator of the invention, may be carried and transported when not in use.

The preferred form of the cable operated hydraulic actuator of the present invention is disclosed in FIGS. 1 to 8 inclusive of the drawings.

General reference is made to the specific features of the present invention by way of the diagrammatic views, FIGS. 7 and 8.

Mounted in a lower portion 14 of the cable tool casing 14) is a hydraulic operated clam actuating cylinder 54 having a plunger 56 pivotally connected to the clams by means of a central pivot pin 58, shown in FIG. 5 of the drawings. The plunger 56 is retractable and extendable relative to the lower end of the casing 10 to cause open and closing movement of the clams 12 which are individually pivoted to the lower end 14 of the casing 10 by means of links 59. These links 59 are pivotally mounted to the clams at their lower ends by means of pins 60 and the upper ends of the links 59 are pivotally mounted to the lower end 14 of the housing 10 by means of pins 62, all as shown best in FIG. 5 of the drawings.

The hydraulic cylinder 54 is provided with a conduit 64 communicating with the interior thereof normally below the plunger piston 66 and a conduit 68 communicates with the upper portion of the cylinder 54 normally above the plunger 66. A flow rate control restrictor valve 70 is in the conduit 68 to control the rate of flow therethrough, as will be hereinafter described. The conduit 68 communicates directly with the interior of a charge cylinder 72 having a plunger 74 coupled with the fitting l6, hereinbefore described. The fitting 16 is secured to the cable 18, all as shown best in FIG. 1 of the drawings.

Referring again to FIGS. 7 and 8, it will be seen that the conduit 68 communicates with a conduit 76 and a hydraulically operated pressure responsive actuator 78 which is responsive to low fluid pressure to cause opening of a two-way valve 88 which is a normally closed valve disposed to control flow between hydraulic conduits 82 and 84. The conduit 82 communicates with a fluid pressure accumulator 86 while the conduit 84 communicates with a fluid pressure responsive actuator 38 having a plunger 90 disposed to open a one-way check valve 92 interconnecting a conduit 94 and the conduit 64.

Communicating with the conduit 68 is a hydraulic charge valve 96 disposed to charge the cylinders 54 and 72 with hydraulic fluid. This charge valve 96 is a check valve type and is utilized to fill the cylinders 54 and 72 with hydraulic fluid. Conventional compressable fluid bleed means is provided to remove all compressable fluids from this side of the system when hydraulic fluid is charged thereinto.

Communicating with the fluid pressure accumulator 86 is a compressable fluid charge valve 98 through which nitrogen or other inert gas may be charged into the top of the accumulator to provide a compressable fluid medium in which pressure energy may be stored, as will be hereinafter described. 7 v

Communicating with the conduit 9- below the level of the accumulator 86 is a hydraulic fluid charge valve 100 which is disposed to charge the lower portion of the accumulator system with hydraulic fluid. This charge valve 153i} is also a check valve and permits the filling of the lower portion of the accumulator 86 and the cylinder 54- with the plunger 56 retracted, all as shown best in FIG. 7 of the drawings.

It will be seen that the check valve 92 normally permits flow of fluid only from the conduit 64 into the conduit 94 and normally prevents flow in the opposite direction. However, actuation of the actuator 88, by pressure fluid from the accumulator 86 through the valve 80* when open, will cause the plunger 90 to open the check valve 92 and permit fluid flow from the conduit 94 to the conduit 64 and this operation occurs, as will be hereinafter described, to actuate the clams 12 to closed position.

With reference to the specific details of construction, of the invention, attention is called to FIG. 6 of the drawings wherein the mechanical assembly of the cable operated hydraulic actuator is disclosed.

As shown in FIG. 6 of the drawings, the cable tool casing is composed of three sections 101, 102, and 103. These sections are hollow tubular structures preferably made of steel tubing. Bolted to a heavy plate 104,

welded or otherwise secured to the upper end of the tubing section 101, by means of bolts 106, is the charge cyl inder 72.

The normally lower end of the casing section 101 is provided with a flange 108 bolted to a flange 1 10 of the casing section 102 by means of bolts 112.

The lower end of the casing section 102 is provided with a flange 114 which bears against a plumbing block 116, the lower side of which engages a flange 118 of the casing section 103. The plumbing block 116 is held between the flanges 114 and 118 by means of bolts 120.

The plumbing block 116 contains the various conduit portions 82, 84, 94 and conduit portions communicating with the charge check valves 96, 98, and 100, as shown in FIGS. 4, 7 and 8 of the drawings. The valve 80, pilot valve 78, and the check valve 92 are all mounted on the plate 116 and likewise, the accumulator 86, by means of a short tubular section of the conduit 82, is carried on the plate 116 concentrically thereof.

A small tube 99 extends from the top of the accumulator to the charge valve 98 via a conduit section 105 in the block 116. The rate orifice 70 is mounted on the lower side of the block 116 by conventional pipe fittings and a portion of the conduit 68 is formed by the block which connects respective portions of the conduit 68 above and below the block.

The lower end of the casing section 103 is provided with a mounting plate 122 on which a flange 124 of the Work cylinder 54 is secured by means of bolts 126. It will be seen that the various hydraulic equipment of the present invention is compactly carried in the casing 10 consisting of the sections 101, 102, and 103.

In operation, the preferred embodiment of the present invention, as shown in FIGS. 1 to 8, inclusive, functions as follows.

When the winch 22 is actuated to withdraw the cable 18 upwardly and when the stop block is engaged by the upper end plate 104 of the casing 10, the plunger 74 of the charge cylinder is retracted whereby the piston 75 is moved upwardly in the cylinder 72 thereby exhausting hydraulic fluid through the conduit 68 and into the upper portion of the cylinder 54. As an example, the line pull on cable 18 may exceed 10,000 pounds if desired, so that considerable force may be applied in ejecting the hy draulic fluid from the upper portion of the cylinder 72 into the upper portion of the cylinder 54 thereby driving the piston 66 of the plunger 56 forcefully downward in the cylinder 54 and forcefully ejecting the hydraulic fluid in the lower portion of the cylinder 54 through the conduit 64 and through the check valve 92 into the accumulator 86 thereby compressing the inert nitrogen or other gas therein to store pressure fluid energy.

With the downward movement of the piston 66 in the cylinder 54, the plunger 56 is forced outwardly moving the pivot pin 58 of the clams 12 downwardly and thereby causing them to open. At the same time, the

casing 10, due to line pull on the cable, is snubbed against the angular stop block 28 and is caused to swing out of vertical position into an acute angular position relative to the vertical, whereupon the casing 10 attains the position B as the clams 12 open to dump dirt in the pile C, as shown in FIG. 2 of the drawings, laterally of the hole A being drilled.

The winch 12 may then be actuated in reverse to permit the cable to play out and let the casing swing back into alignment with the hole A so that the casing 10 and the clams 12 on the lower end thereof may be lowered into the hole for the next digging operation.

As the clams 12 come to rest in the bottom of the hole and slack on the cable 18 is continued, the pressure responsive pilot 78, being responsive to reduced pressure in the conduit 68, actuates. It will be understood that normally the weight of the casing 10 and its contents, including the hydraulic equipment is suflicient to maintain a predetermined pressure in the conduit 68 and on the pilot 78 to prevent it from actuating. However, when the load of the casing 10 and its contents rests upon the clams 12, in the bottom of the hole, and the cable 18 is further slackened, pressure in the conduit 68 drops to a minimum and the pilot 78 then actuates. This pilot is a conventional spring loaded pilot which causes opening of the valve 80. At this time, the piston 66 and plunger 56 are in the position shown in FIG. 8 of the drawings, and the clams are open and resting on the bottom of the hole. When the valve 80 is thus actuated, pressure fluid from the accumulator 86 is transmitted to the check valve pilot 88 causing its plunger 90 to force the check valve 92 off its seat. Pressure fluid then travels through the conduit 94 and into the conduit 64 and into the cylinder 54 below the piston 66 forcing the plunger 56 upwardly and forcefully closing the clams 12 thereby digging another load of dirt from the bottom of the hole.

At this time, the Winch 22 is again energized to retract the cable 18 upwardly whereupon the upper end of the casing 10 is again engaged with the stop block 28 and the clams 12 are opened and dumped, as hereinbefore described.

A modified actuating system for the clams 12 may include a semi-manual operation comprising the use of a solenoid valve in place of the valve 80 and the pilot 78. If the invention is modified to utilize a solenoid valve in place of the valve 80 and the pilot 78, an electrical conductor 128 is coupled to the modified valve 80 in order to provide power to actuate the solenoid thereof and to permit hydraulic .flow from the conduit 82 to the conduit 84. Under such conditions, the valve solenoid is provided with a ground connection 130 which may be electrically coupled to the cable 18 and hence to the truck frame 44. The truck battery 132 which supplies energy through a manually operable switch 134 to a conventional slip ring conductor reel 136 to which the conductor 128 is connected. As shown in the modification disclosed in FIG. 3, the switch 134 may be suspended from a manual control connected to the reel 136 and the conductor 128 passing from the reel 136 is coupled to the casing 10 whereby the reel 136 plays out the conductor 128 when the casing goes down the wellhole A and retracts the conductor 128 when the cable tool casing 10 is retracted from the hole A.

Therefore, according to the modification of the invention and the conversion of the valve 80 and its pilot 78 to a solenoid valve, the clams 12 may be closed in accordance with a manual operation of the switch 134.

Starting and stopping control of the winch 22 may also be controlled by additional switches similar to the switch 134 which may be carried in the same switch housing, if desired.

In the modification of the invention, as disclosed in FIGS. 9 to 13 of the drawings, the upper end of the cylinder 54 communicates with the upper end of the cylinder 72 via the conduit 68. Communicating with this conduit 68 through a short conduit 138, is a pressure:

responsive valve 140 communicating with the pilot 78 to* actuate the valve 80.

' A conduit 142 communicates with the valve 89 and an opposite end 144 of this conduit 142 communicates withv hydraulic pressure fluid in a lower potrion of the accumulator 86 which is charged with nitrogen or other inert gas above the hydraulic fluid.

The valve 80 also communicates with a conduit 146 connected to the conduit 64 which is coupled to the normally lower end of the cylinder 54. The valve 80,. according to this modification, is used only to conduct the flow of hydraulic fluid from the bottom of the cylinder 54 back to the accumulator 86.

A mechanically actuated control valve 148 is provided with an inlet conduit communicating with the conduit 142 and pressure fluid in the lower portion of the accumulator 86. Also coupled to the valve 148 is an outlet conduit 152 which is coupled to the conduit 64 communicating with the lower portion of the cylinder 54.

The valve 148 is actuated, as shown in FIG. 10, by mechanism coupled to the charge cylinder plunger 74'. The valve 148 is thus actuated when the clams 12 are in the bottom of the hole and when slack of the cable 18 permits pressure in the cylinder 72 and conduit 68 to reach a minimum.

Referring specifically to FIG. 10 of the drawings, it will be seen that the plunger 74 is reciprocally mounted in a hollow tubular piston rod 154 to which the plunger piston 75 is connected. The plunger 74 is provided with a pilot engaging rod 156 on its lower end which actuates a plunger 158 of the valve 148 when slack in the cable 1% permits downward movement of the plunger 74 urged by a weight 159 carried thereon and supported by a spring 160 retained by a flange 162 on the lower end of the plunger 74. Thus, when the plunger 74 carries the piston 75 upwardly, the spring loaded plunger of the valve 148 which is normally closed is permitted to move upward and close the valve 148 whereupon downward movement of the plunger 74 and bearing of the weight 159 thereon causes the actuating rod 156 to press downwardly on the valve actuating rod 158 and to open it thereby permitting pressure fluid to flow through the conduits 150, 152 and 64 to the bottom of a cylinder 54 and to raise the plunger 56 and close the clams.

A check valve 164 is installed in the hydraulic circuit to transfer oil leakage from the working system to the accumulator system to maintain a fluid balance in the system.

When pressure fluid leaks around the piston 66 and increases the supply of fluid in the cylinders 54 and 72, the fluid may then escape through the check valve 164 and into the conduit 142 in the accumulator side of the system.

As shown in FIGS. 9 and 10 of the drawings, the specific construction of the accumulator 8 6 includes a movable piston 166 which stands above the hydraulic fluid in the accumulator and separates the compressible fluid such as compressed nitrogen or the like, from the hydraulic fluid. It will be seen that the casing 10, shown in FIGS. 9 and 10 of the drawings, encloses all of the hydraulic equipment of the present invention in a similar manner to that hereinbefore described in connection with FIGS. 1 to 8 of the drawings.

Likewise, the clams 12 are similarly mounted on the lower end of the cable tool casing, as hereinbefore described in connection with FIGS. 1, 2, and 5 of the drawings.

It will be obvious to those skilled in the art that various modifications of the present invention may be resorted to in a manner limited only by a just interpretation of the following claims.

I claim:

1. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close;

a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating With the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams.

2. In a cable operated hydraulic actuator the combina tion of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; a second conduit of said conduit means directly interconnecting and communicating with the interiors of said first and second cylinder means whereby pressure fluid is conducted from said second cylinder means to said first cylinder means to cause actuation of said clams to open position during the application of said charging force by said cable.

3. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; a second conduit of said conduit means directly interconnecting and communicating with the interiors of said first and second cylinder means whereby pressure fluid is conducted from said second cylinder means to said first cylinder means to cause actuation of said clams to open position during the application of said charging force by said cable; said second conduit communicating with one side of said plunger of said first hydraulic cylinder means, an opposite side of said plunger of said first hydraulic cylinder means communicating with said pressure fluid accumulator.

4. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is iabutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fiui-d from said accumulator into said first hydraulic cylinder means tending to close said digging clams; a second conduit of said conduit means directly interconnecting and communicating with the interiors of said first and second cylinder means whereby pressure fluid is conducted from said second cylinder means to said first cylinder means to cause actuation of said clams to open position during the application of said charging force by said cable; said second conduit communicating with one side of said plunger of said first hydraulic cylinder means, an opposite side of said plunger of said first hydraulic cylinder means communicating with said pressure fiuid accumulator; a check valve in said second conduit communicating between said accumulator and said first hydraulic cylinder means disposed to prevent fiow from said first hydraulic cylinder means to said accumulator means and disposed to prevent fluid flow from said accumulator to said first hydraulic cylinder means.

5. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; a second conduit of said conduit means directly interconnecting and communicating with the interiors of said first and second cylinder means whereby pressure fluid is conducted from said second cylinder means to said first cylinder means to cause actuation of said clams to open position during the application of said charging force by said cable; said second conduit communicating with one side of said plunger of said first hydraulic cylinder means, an opposite side of said plunger of said first hydraulic cylinder means communicating with said pressure fiuid accumulator; a check valve in said second conduit communicating between said accumulator and said first hydraulic cylinder means disposed to prevent flow from said first hydraulic cylinder means to said accumulator means and disposed to prevent fluid flow from said accumulator to said first hydraulic cylinder means; and control valve means operable to conduct pressure fluid from said accumulator to said first hydraulic cylinder means.

6. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereby by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydnaulic cylinder means tending to close said digging clams; a second conduit of said conduit means directly interconnecting and communicating with the interiors of said first and second cylinder means whereby pressure fluid is conducted from said second cylinder means to said first cylinder means to cause actuation of said clams to open position during the application of said charging force by said cable; said second conduit communicating with one side of said plunger of said first hydraulic cylinder means, an opposite side of said plunger of said first hydnaulic cylinder means communicating with said pressure fluid accumulator; a check valve in said second conduit communicating bet-ween said accumulator and said first hydraulic cylinder means disposed to prevent flow from said first hydraulic cylinder means to said accumulator means and disposed to prevent fluid flow from said accumulator to said first hydraulic cylinder means; and control valve means operable to conduct pressure fluid from said acculator to said first hydraulic cylinder means; a solenoid disposed to operate said control valve means.

7. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; a second conduit of said conduit means directly interconnecting and communicating with the interiors of said first and second cylinder means whereby pressure fluid is conducted from said second cylinder means to said first cylinder means to cause actuation of said clams to open position during the application of said charging force by said cable; said second conduit communicating with one side of said plunger of said first hydraulic cylinder means, an opposite side of said plunger of said first hydraulic cylinder means communicating with said pressure fluid accumulator; a check valve in said second conduit communicating between said accumulator and said first hydraulic cylinder means disposed to prevent flow from said first hydraulic cylinder means to said accumulator means and disposed to prevent fluid fiow from said accumulator to said first hydraulic cylinder means; and control valve means operable to conduct pressure fluid from said accumulator to said first hydraulic cylinder means; a pressure responsive means for operating said control valve; said pressure responsive means communicating with pressure fluid in said second conduit whereby said pressure responsive means operates said control valve in response to a reduction in pressure within said second hydraulic cylinder means which occurs when said clams engage the earth and support said casing and when respective upward force of said cable is at a minimum.

8. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; said valve means comprising first and second valves, said first valve disposed to conduct pressure fluid from said first cylinder means to said accumulator; said second valve disposed to conduct pressure fiuid from said accumulator to said first hydraulic cylinder means.

9. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; said valve means comprising first and second valves, said first valve disposed to conduct pressure fluid from said first cylinder means to said accumulator; said second valve disposed to conduct pressure fluid from said accumulator to said first hydraulic cylinder means; means operable in response to a reduced load on said cable for opening said second valve.

10. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively mov able plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; said valve means comprising first and second valves, said first valve disposed to conduct pressure fluid from said first cylinder means to said accumulator; said second valve disposed to conduct pressure fluid from said accumulator to said first hydraulic cylinder means; means operable in response to a reduced load on said cable for opening said second valve; comprising a mechanical plunger connected to the plunger of said second hydraulic cylinder means.

11. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means; said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; said valve means comprising first and second valves, said first valve disposed to conduct pressure fluid from said first cylinder means to said accumulator; said second valve disposed to conduct pressure fluid from said accumulator to said first hydraulic cylinder means; means operable in response to a reduced load on said cable for 14 opening said second valve; comprising a pressure fluid responsive means disposed to open said second valve, said pressure responsive means disposed to sense the pressure of fluid in said hydraulic cylinder means.

12. In a cable operated hydraulic actuator the combination of: a casing; digging clams mounted on a lower end of said casing and movably disposed to open and close; a first hydraulic cylinder means having a plunger, said first hydraulic cylinder means coupled to said casing and said clams and disposed to open and close said clams; a second hydraulic cylinder means having relatively movable plunger and cylinder parts, one of said parts coupled to said casing; a pressure fluid actuator in said casing; conduit means communicating with said accumulator and with said first and second hydraulic cylinder means; a cable coupled to the other of said relatively movable parts of said second hydraulic cylinder means, said cable suspending said casing and said clams; stop means forming an abutment disposed to limit upward movement of said casing during elevation thereof by said cable; means for forcefully retracting said cable when said casing is abutted by said stop means, whereby said cable exerts charging force to cause relative movement of the plunger and cylinder of said second hydraulic cylinder means; a conduit means communicating with the interiors of said first and second hydraulic cylinder means and said accumulator whereby action of said cable when exerting said charging force tends to cause charging of pressure fluid into said accumulator; and valve means operable to conduct pressure fluid from said accumulator into said first hydraulic cylinder means tending to close said digging clams; said valve means comprising first and second valves, said first valve disposed to conduct pressure fluid from said first cylinder means to said accumulator; said second valve disposed to conduct pressure fluid from said accumulator to said first hydraulic cylinder means; means operable in response to a reduced pressure in said cylinder means for opening said first valve and permitting the flow of pressure fluid from said first cylinder means to said accumulator; and means mechanically responsive to the downstroke of the plunger of said second cylinder means disposed to open said second valve to conduct pressure fluid from said accumulator to said first hydraulic cylinder means.

No references cited. 

1. IN A CABLE OPERATED HYDRAULIC ACTUATOR THE COMBINATION OF: A CASING; DIGGING CLAMS MOUNTED ON A LOWER END OF SAID CASING AND MOVABLY DISPOSED TO OPEN AND CLOSE; A FIRST HYDRAULIC CYLINDER MEANS HAVING A PLUNGER, SAID FIRST HYDRAULIC CYLINDER MEANS COUPLED TO SAID CASING AND SAID CLAMS AND DISPOSED TO OPEN AND CLOSE SAID CLAMS; A SECOND HYDRAULIC CYLINDER MEANS HAVING RELATIVELY MOVABLE PLUNGER AND CYLINDER PARTS, ONE OF SAID PARTS COUPLED TO SAID CASING; A PRESSURE FLUID ACTUATOR IN SAID CASING; CONDUIT MEANS COMMUNICATING WITH SAID ACCUMULATOR AND WITH SAID FIRST AND SECOND HYDRAULIC CYLINDER MEANS; A CABLE COUPLED TO THE OTHER OF SAID RELATIVELY MOVABLE PARTS OF SAID SECOND HYDRAULIC CYLINDER MEANS, SAID CABLE SUSPENDING SAID CASING AND SAID CLAMS; STOP MEANS FORMING AN ABUTMENT DISPOSED TO LIMIT UPWARD MOVEMENT OF SAID CASING DURING ELEVATION THEREOF BY SAID CABLE; MEANS FOR FORCEFULLY RETRACTING SAID CABLE WHEN SAID CASING IS ABUTTED BY SAID STOP MEANS, WHEREBY SAID CABLE EXERTS CHARGING FORCE TO CAUSE RELATIVE MOVEMENT OF THE PLUNGER AND CYLINDER OF SAID SECOND HYDRAULIC CYLINDER MEANS; A CONDUIT MEANS COMMUNICATING WITH THE INTERIORS OF SAID FIRST AND SECOND HYDRAULIC CYLINDER MEANS AND SAID ACCUMULATOR WHEREBY ACTION OF SAID CABLE WHEN EXERTING SAID CHARGING FORCE TENDS TO CAUSE CHARGING OF PRESSURE FLUID INTO SAID ACCUMULATOR; AND VALVE MEANS OPERABLE TO CONDUCT PRESSURE FLUID FROM SAID ACCUMULATOR INTO SAID FIRST HYDRAULIC CYLINDER MEANS TENDING TO CLOSE SAID DIGGING CLAMS. 